Muzzle brake, thread protector, barrel harmonics and accuracy

Len Backus

Staff member
May 2, 2001
I am building a personal rifle with a brake and may utilize a thread protector to replace the brake for occasional use when I'll have a hunting partner nearby and don't want the brake's muzzle blast to impact the health of his ears. I always wear protection, braked or not.

I know from experience in using a rotating, tunable brake (Que Industries) that the length, weight, position of anything appended to the end of a barrel can affect accuracy.

Does anyone have experience to say whether I should be concerned with this? Common sense says build the thread protector to be as close as possible to the mass and shape of the brake.
I dont have any personal experience with that Len, but you may be on to something with a thread protecter of simmilar size shape and wt. I dunno. From what Ive hered about taking your brake off and adding a therad protecter, is your P.O.I. will change slightly, due to harmonics etc. and you need to dope it with a brake and with a cap. But never hered of anyone trying it with a cap like that. Maybe J E Customs, or 308 Nate would know. Sounds like a cool experiment.
I discussed this with Kirby when he built a rifle for me a few years ago. He said about the best a person could do is build a blank threaded cap the same weight as the brake and cross your fingers & hope for the best. He also told me that most customers that ask for the blank cap never use it. I've helped prove his observation true. It sounded like a good idea to me at the time so I had him build a blank thread protector for the same reasons you've expressed. I can't tell you whether or not POI changes because I've never screwed it on the end of my 300 Win Mag barrel. Not sure if I could even find mine now.
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i always carry extra ear plugs, last time at the range checking drops before the hunt i made my guide put in ear plugs before i would even open my box of ammo. Easier to get the guide to put in some ear plugs than work up two sets of drops or a custom muzzle break, IMO.

There will always be a harmonic shift in the barrel changing from a brake to no brake even if you have a thread protector the exact same weight unless the length and proportions are the same. In other words, a thread protector may weight the same as the brake but unless that weight is the same amount of distance from the end of the barrel, it will be at least slightly different.

It is not just the weight of the accessory on the end, but also it's position. Even if you could get this all worked out which would be very difficult due to all the holes and subsequent distribution of that weight due to the holes, there is still the factor of the gasses smacking the *** end of the bullet differently. At the very least, you will have a POI shift if not a MOA size increase or decrease and probably both.

The best thing is obviously to develop your load(s) either with or without your brake and test them with the opposite. You will see first hand how easily things can often change with just a wee bit of difference in either weight, gas distribution or both on the end of your stick. If you are really lucky, these effects will be very minimal.
Michael thanks, yes, that is what I expect based on my extensive experience with the Que.
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